1. Field of the Invention
Blower assemblies for vehicles are airflow in a scroll housing, and in particular is concerned with a baffle mounted on an interior surface of a scroll housing for reducing airflow noise.
2. Description of the Related Art
Blower assemblies for vehicles are well-known. In general, an assembly includes a blower motor and fan mounted on a scroll housing. The scroll housing is mounted to a surface of the dash panel adjacent the engine compartment of the vehicle. Air is drawn along the axis of the fan into the scroll housing and exits tangentially from the fan blades.
Fans used in automotive applications usually have economical, forward-swept blades. In most vehicular heating/air conditioning systems, a fan will operate at certain times in the surge or stall regions. Such operation can result in dramatic increases in noise caused by unstable and unsteady airflows in these regions. The noise can be described as a low frequency, oscillatory rumble. This rumble is caused by vortex shedding and the resulting instability of airflow exiting a blade and subsequent reattachment to the next blade as the fan rotates, and is known as Helmholtz type of resonance. Such noise has also been observed in axial flow compressors.
The art continues to seek improvements. It is desirable to utilize a blower assembly and scroll housing for use with a heating/air conditioning system of a vehicle. Furthermore, it is desirable that the low frequency, oscillatory rumbles which occur in conventional systems be reduced or eliminated.